Method and apparatus for making flexible tubes



June 27, 1950 w. s. PRENDERGAST 2,513,106

memos AND APPARATUS FOR MAKING FLEXIBLE TUBES Original Filed Feb. 8, 1947 2 Sheets-Sheet l wig ,Ex uJDE K HBCD C 6045 5 i 6 INVENTOR.

I 8 ByWRl-TER 5. PRENoznaAs ATTORNEYS June 27, 1950 w. s. PRENDER GAST METHOD AND APPARATUS FOR MAKING FLEXIBLE TUBES Original Filed Feb. 8, 1947 2 Sheets-Sheet 2 AIIIIII IN VEN TOR.

Patented June 27, 1950 timemimmiusriamx ELEXJBEE Walter S. -Prendergast, Maced Original. applicationEehru-arg.8 727,464; Divided and miss s itti t i hio- 3.947

11 Claims.

This invention is concerned with a method and s apparatus for makinga reinforced plastic tube. suitable for use in vacuum cleanersandother installations Where a flexible non-collapsible tube with smooth interior is desired. 'lhisapplication is a division of my application, Ser. No. 727,464, filed February 8, 1947, for areinforced plastic tube and method and apparatusfor making the same.

The tube, as made by mymethod and apparatus, comprises an inner tube of thermo pla'stic materiaLa'helical reinforce of wire surrounding and engaging such inner tube, and an outer tube of thermo-plastic material surrounding the wire helix and corrugated inwardly between coils of the helix to contactwith the inner tube and ad' here firmly to it. The object of the present invention is to provide for the making of suchtube byan efiicient extruding process associated with other simple steps.

Mymethod and apparatus are illustrated in the drawings hereof and hereinafter described and the essential novelieatures are set out in the claims, I i

In the drawings, Fig. 1' is a diagrammatic plan of my apparatus formaking this tube by themethod of'this invention; Fig. 2 is an enlarged axial section through either of the two tube mills employed in theprocess; Figs. 3 to 6- inclusive are diagrams illustrating successive stages ofthe to Carter 'Products Corp ati e Ohimacorporatiombf Ohio} 194m, se ia p1 icaJ- i e 1r,

sageway communicates by a I -extension 2'3? with the"- discharge end ofi=the tubing machine. Each barrel 2!) or 20a has a converging: nozzle liii lead ing toward the discharge end of the passageway 22.

It results from the above construction that;

I. the hot plastic material" extruded by the extube as it is-built upon the mandrel; Fig. "I- is a crosssection of the complete tube; Fig. 8 is a diagrammatic view illustrating the tube in one vacuum cleaner installation.

In Fig; 1, Hi and Ba indicate a pairof plastic extruding machines, each of which is shown in a axial section in Fig. 2, Briefly, the extruding machine comprises a hollow barrel H (Fig. 2 having a central bore in which is'a rotatable screw l2- for forcing tubular plastic material,

received from a hopper l3; out of the discharge end of the barrel. Suitable motor mechanism I4 operates to rotate the screw. At its discharge end the barrel is preferably continuedby a 1 01- low bonnet l5 surrounding an unthreadedpilot' constitutingthe end portion of the screw; The

barrel proper and the bonnet are shown as hav-' ing-annular chambers I6, I! which may be supplied with steam. from, suitable heaters, indicated at B.

Beyond: the discharge end ofthe twobonnets I5 are hollow barrels 20 and 20a similarly con-- structed and aligning with each other. Each barrel, carries an internal tubular plug 2,! pr o vidina n, an assa e a 2,-, eeni exterior of the plug andthe barrel. This -pastru'ding machine I0 passes into the barrel 20 andemergesin contracted. tubular form, as indicated. at 25 in Fig. 2. Along straight cylindricalmandrel is inserted through the tubular plug 2| and'is forced alongthe same as the material is extruded, so that the inner layer for complete tube 'd'esignated A is termed on the traveling mandreh a ve-'shown at (H- a support for the: mandrel andat. 32 a motor mechanism for propelling-"it. After the mandrel emerges from the tubing -he'adf 20 carrying thehot plastic tube it'- proceeds across a suitable coolershown: at 35 in.

Fig. 1, which-may -for'instance spray water onto.

the hot tube;and then passes into cooperation withfa wire winder 36} of any suitable formwhich winds a-wire around the tubethe tubeon. the mandrel i's mov-ing forwardly, this winding becomes the helixB. l

The mandrel carryingtlie inner tube andsthei embracing helix. of wire nowpasse'sv through the. head- 2621 which is similar.- tothe head: Mi-,1 though. having a larger borei'in the-tubular plug. In passing through this head the. outer layer. of plasticmaterial is formed. about. the Wire. helix and inner tube. The. mandrel: continues to. pro. gress and th' compositetubewith this outerlayer; 0: then. passes along. a. conveyor til; into... coactiorr, with a. c'onrugatingl device. 38; which. may; come. priseone i on IDOI.B{.1'611QIS1 engaging: the outer. tube; This corrugating. device serves to -.diyertthe outer. tube inwardly. between. the coils. of; the. wire. as; indicated at DLinFigS'. and 6;:

The. complete: tube now. passes. into. the.v action ofia cooler: which may; be a. conveyor: 39:. which. delivers. the.- tube; mounted: on itsmandrel. After.- this, the finished tubemay be. cut in proper secs. tionsand stripped; fromthermandrel ,It. is. to :be: understood: that. the mandrels. are. of considerable; length, as mostdesired for. the; length of theztube to be.-iormed;.and one mandrel; follovis/direritlmafter; another. Such following mandrel; advanced by; the motor mechanism; 32", serves; to; shove; thei advance;rnamirel ahe ad; of= it. :When the; tuhe has: been completed: it. is. light; illi weight-hue very strong; as; a. perfectly. smooth. uninterruptedrinterior; well adapted: for vacuum cleanerzsworknandsit cannotbe collapsed, but,

may betfiexed aS'idfiSited imuse, lmFig. 8, khaye:

illustrated one such use where E indicates a vacuum cleaner nozzle on the end of a tubular handle F to which is attached my composite tube A, B, C, D leading toa suction apparatus G. This illustration of course represents merely one use for the tube.

I may employ for the manufacture of the tube, v

by this method and apparatus, any suitable thermo-plastic material of such composition and consistency that it may be formed into a tube by the tubing machines and upon cooling will make an efiective permanent" impervious tube adapted to retain the general satisfactory form given it in the forming operation but flexible in use. As an illustration, however, I may state that I have used satisfactorily vinylchloride as a material for the'tube, also vinylchloride copolymerized with other materials such as vinylacetate or vinylformate. The reinforcing wire may be steel or plastic material having suflicient rigidity to prevent collapsing of the tube, while allowing flexure thereof.

I claim:

l. The method of making flexible tubes comprising extruding plastic material in tubular form about a traveling mandrel to make an inner layer, surrounding the inner layer by a reinforce, placing a tubular covering over the reinforce, forcing the outer layer inwardly inregions clearing the reinforce to pocket the reinforce between the layers, and stripping the tube from the mandrel.

2. The method of making flexibletubes comprising forming an inner layer of plastic material about a traveling mandrel, surrounding the inner layer by a reinforce, extruding plastic material in tubular form about the reinforced inner layer to form an outer layer, causing the inner and outer layers to adhere to each other in separated regions to retain the reinforce in position, and stripping the tube from the mandrel.

3. The method of making flexible tubes comprising extruding plastic material of tubular form to make an innerlayer, thereafter surrounding the inner layer by a reinforce, extruding plastic material in tubular form about the reinforce to form an outer layer and causing the inner and outer layers to adhere to each other periodically to retain the reinforce in position.

4. The method of making flexible tubes comprising extruding plastic material of tubular form about a traveling mandrel to form an inner layer, surrounding the inner layer by a helical reinforce, extruding plastic material in tubular form about the helical reinforce to form an outer layer, causing the inner and outer layers to adhere to each other between the turns of the reinforce, and stripping the-tube from the mandrel.

5. The method of making a flexible reinforced tube comprising extruding thermo-plastic material in tubular form about a traveling mandrel, cooling said layer, placing a reinforce about the exterior of the layer, forming a tubular covering over the reinforce,- forcing the outer covering inwardly into contact with the inner layer to position the reinforce between the layers, and stripping the tube. from the mandrel.

6. The method of making a flexible reinforced tube having an uninterrupted inner surface comprising extruding thermo-plastic material in tubular form about a traveling cylindrical mandrel, winding a helical coil of wire about the tubular inner layer, extruding a second tubular layer to cause it to'cover the'helical reinforce,

forcing the outer layer inwardly between the coils of the wire into adhering contact with the inner layer, cooling the respective hot layers to form pliant compact members with smooth external surfaces, and stripping the tube from the mandrel.

7. The method of making a flexible reinforced tube comprising extruding thermo-plastic material in tubular form about a traveling mandrel, cooling the layer thus formed as the mandrel progresses, winding a helical coil of wire about the inner tubular layer, extruding a second tubular layer of thermoplastic material over the inner layer and reinforce, cooling such second layer, corrugating the outer layer inwardly between the coils of the wire and causing it to adhere in such regions to the inner layer, and stripping the tube from the mandrel.

8. An apparatus for making reinforced flexible tubes comprising tw extruding machines discharging into aligned hollow heads, means for progressing a succession of mandrels each shoving one ahead of it through the two heads so that the tube formed at the second head covers the tube formed at the first head.

9. An apparatus for making reinforced flexible tubes comprising two extruding machines discharging into aligned hollow heads, means for progressing a mandrel successively through the two heads with the tube formed by the first head being exposed between the heads, means for applying a reinforce to such exposed portion of the tube formed about the mandrel at the first head so that the tube formed at the second head covers the tube formed at the first head and the reinforce thereon.

10. An apparatus for making reinforced flexible tubes comprising means for progressing a cylindrical mandrel in the axial direction, an extruding machine discharging into a hollow head surrounding a mandrel to form a plastic tube about the mandrel, a wire winder adapted to coil a wire in helical form about the advancing inner tube on the mandrel, a second extruding machine having a hollow head adapted to surround the mandrel, the inner tube and the helix f wire, and mechanism for thereafter corrugating the outer tube inwardly against the inner tube while the latter is supported by the mandrel.

11. An apparatus for making flexible reinforced tubes comprising a cylindrical mandrel, mechanism for progressing the same axially of the mandrel, an extruding machine adapted to force thermo-plastic material in heated condition about the mandrel as it advances, a cooling device to cool such inner tube on the mandrel, a winding device adapted to wind a coil of reinforce material about the cooled inner tube on the mandrel, a second extruding machine adapted to deliver an outer tube of thermo-plastic material about the advancing coil on the inner tube on the mandrel, and a corrugating device to force the outer tube inwardly between the coils of the reinforce into contact with the inner tube while the latter is held in cylindrical form on the mandrel.

WALTER s. PRENDERGAST. REFERENCES CITED The following references are of record the file of this patent:

FOREIGN PATENTS Country Date Great Britain M ay 17,193;

Number 

